Telegraph station selector



8, 1956 R. G. WAMPACH TELEGRAPH STATION SELECTOR Filed Dec. 28, 1954[NVENTOR ROBERT G. WAMPACH ATTORNE TELEGRAPH srArroN SELECTOR Robert G.Wampach, Rosette, lIiL, assignor to Teletype Corporation, @hieago, Ill.,a corporation of Delaware Application December 28, 1954,. Serial No.478,105 9 Qiaims. (CL 173--4.1)

This invention relates to telegraph station selectors and moreparticularly to station selectors incorporated as components at eachstation of a multistation system whereby selective intercommunicationover a common signaling channel may be obtained between variousarrangements of the stations.

Many telegraph systems have been devised to provide for the selectiveintercommunication of a transmitting station with varying numbers ofreceiving stations. These systems can in general be placed in two broadcategories; namely, those systems wherein all or a number of thestations can be interconnected through the agency of a switching centerand those systems wherein each station is permanently held in operativeassociation with a single communication channel, but where certain. ofthe stations can be rendered nonresponsive to the recordation ofsubsequently transmitted messages. The present invention relates to thelatter of these systems which. in general depend for operation upon theutilization of electromag netic relay or mechanical time delay devicesfor the selection of stations to record transmitted messages. The use ofelectromagnetic relays: as time; delay devices presents seriouscomplications when such relays. are incorporated as line relays becausethe inductance of these relays must be held at a minimum, otherwisedetrimental inductance is introduced into the transmission line. Whenconsideration is given to the factor that. inductance must be held to aminimum and that the time of delay is of critical significance then itis apparent that existing; electromechanical time delay devices provideonlymarginal delays and after a period of time the delay attained withthese devices is unpredictable.

Usually when time delay relays are incorporated into a transmissionline, the actuation of the. outlying, receiving stations is attained bya prolonged break. in the trans.- mission line; consequently, it may beappreciated that when these systems are transmitting: at relatively slowspeeds the impression of a signal indicative of. ablank will provide abreak in the transmission line of sufiicient duration to trip thestation selecting devices at. all the outlying stations, thus rendering.all the stations responsive to the subsequently transmitted portions ofthe message.

A primary object of this. invention is to provide telegraph stationselectors utilizing simple, economical and dependable components.

In adjunct with the first object it. is. a further. object to provide astation selector devoid of any marginal electromagnetic or mechanicaltime: delay devices.

A further and more finite object of the invention: resides in theprovision of telegraph station selectors utilizing electronic timingdevices having improved operating margins.

Another object of the invention resides in station selectors havingreadily adjustable time delay devices. adapted to be actuated by avariety of. different multielement codes or upon application of signals.transmitted atv different transmitting speeds.

ed States .Patent r. w 0 l) The present invention is described inrelation to a printing telegraph apparatus of the type shown in thepatent to S. Morton et al., No. 1,904,164, dated April 18, 1933, whereinselectively operated mechanisms are shown as being capable of closingswitches in response to the receipt of preconcerted telegraph signals.it is to be understood, however, that the present invention is notrestricted to an incorporation in such a printing tele= graph apparatus,but rather is readily adaptable to operate in conjunction with manyother diverse types of telegraph transmitting and receiving equipment.

With these and other objects in view the present invention contemplatesa multistation telegraph communication system permanently interconnectedby a single communication channel and having facilities therein wherebyeach station of the system can initiate a call to any other station inthe system. Initiation of a call is attained by opening the signalingchannel to all the other stations for a time interval determined by theoperation of an electronic timing device, whereby electronic: timingcircuits at all the outlying stations are actuated to start motors fordriving the associated: printing telegraph apparatus.

Facilities are provided at each station so that when a station initiatesa call to the other stations the normally quiescent motor at thisstation is immediately placed in operating condition. Thereafter thecalling station transmits a series of signals indicative of the callingstations and the stations designated to receive the message. Thetransmission of this series of signals actuates locking circuits at the.calling station and the designated receiving stations to hold the motorsthereat in a running condition. In. addition the receipt of the callingsignals at designated stations initiate. the operation ofinstrumentalities to transmit back to the calling station an answer backsignal thereby informing the calling station that the designatedreceiving stations have their respective motors in a locked runningcondition.

Subsequent to the transmission of the call signals, sig nals indicative.of a disconnect function are transmitted over the communication channelto de-energize the motor control circuits at the: stations which .havenot been lockedv and: are not to receive the message. Obviously sincethe printing telegraph apparatuses at the nonselected stations havetheir motors placed in a quiescent state these stations will not causethe recordation of the subcquently transmitted messages.

In order to restore all the stations to an idle condition followingtransmission of a message, preparatory to the transmission of. messagesto other groups of stations, the electronic timing, circuit at theinitiating circuit is again operated whereupon the transmission channelis again interrupted for a prolonged period of time to energize the timedelay circuits at the unoperated stations whereupon the motorsthereatcommence to rotate. The time delay circuits at the previouslyoperated stations are also energizedtodisrupt the locking circuits fortheir respective motors, butv these motors are held operative by anauxiliary locking circuit having included therein a contact adapted. tobe opened by the receipt of a special disconnect signal fromtransmitting or calling station. When the disconnect signal istransmitted over the communication channel, motors at all the outlyingstations are brought. to rest and in addition the locking circuit forthe motor at the transmitting station is likewise. disrupted to bringthe. motor thereat. to a stop. The system is thus placed in anunoperative condition preparatory to the transmission of subsequentmessages to other combinations of stations.

Other objects and advantages of the invention will be apparent from thefollowing detailed description when considered in conjunction with theaccompanying drawing wherein:

Fig. 1 discloses a telegraph communication system embodying theprincipal features of the invention and more particularly the specificcircuits employed at two of the stations together with the mechanicalelements for controlling said circuits.

Referring to the drawing, there are shown two stations and 11 each ofwhich has identical circuitry. Two other stations 12 and 13 are alsoshown in block diagram form; but, it is to be understood that thecircuitry included in these stations is identical to that shown instations 10 and 11. It is to be noted that all the stations 10, 11, 12and 13, are interconnected by a common communication channel which inthis instance is repre sented by a transmission line designated by thereference numeral 14.

Each of the stations is provided with a printing telegraph apparatus ofthe type shown in the afore-identified patent to S. Morten et al.,having selector magnets 16 which are permanently associated with thetransmission line 14. Each printing telegraph apparatus has a keyboardtransmitter whose contacts are designated in this instance by thereference numeral 17. At station 10 one of the key levers representativeof the letter A is shown and denoted by the reference numeral 18. A keylever representative of the printing telegraph apparatus at the station11 is designated by the reference numeral 19. It is understood from theMorton et al. patent that the depression of the key levers 18 and 19results in the permutative positionment of a number of code bars 21 tocontrol the keyboard contacts 17 to impress start-stop signals of theBaudot code on the transmission line 14.

Further, each printing telegraph apparatus at the respective stations isprovided with function levers 22, 23, 24 and 25 of the type shown inFig. 6 in the Morton et al. patent and designated by the referencenumeral 175. In the present invention the function levers 22 are adaptedto be actuated by the receipt of a signal indicative of a space functionwhereas the function levers 23 are adapted to be operated in accordancewith the receipt of a signal representative of a carriage returnfunction. Function lever 24 is adapted to be operated in accordance witha letter code signal which is representative of the identification ofthe station denoted by the reference numeral 10 whereas the functionlever 25 is adapted to be operated in accordance with the receipt of asignal at the station 11 which is representative of the letter codesignal of that station. Each of the stations is also provided with amotor 27 for driving the printing telegraph apparatus thereat and asillustrated in the drawing when the stations are in the idle conditionthe motor circuits are open at contacts 28.

For purposes of illustration assume that circuits at each station 10,11, 12 and 13 are in the idle condition which condition is illustratedin the drawing. When it is desired to initiate a call from a stationsuch as station 10 to station 11 the operator at station 10 momentarilydepresses a start push button 31. Closure of push button 31 appliespositive battery through a normally unoperated contact 32 of a relay 33,through a fixed contact 34, to an unoperated contact 35 of a relay 36,over a lead 37, through an unoperated contact 38 of a relay 39, througha fixed upper contact 45, through the now closed push button 31, througha left-hand coil of a relay 40 to negative battery. Energization of thelefthand coil of relay 40 completes a locking circuit which may betraced from positive battery through a now drawn up contact 41 of therelay 40, through the lefthand coil of relay 40 to negative battery. Inoperating, relay 40 breaks the transmission line 14 at a now openedcontact 42 causing a low inductance line relay 43 to assume a state ofde-energization thereby causing a contact 44 associated therewith tomove from its lower to upper contact.

Prior to the operation of push button 31 a changing circuit existed frompositive battery through the relay 33, through a contact 46, throughunoperated contacts 47 and 48 of the relay 40, through a high resistance49 to a junction point 50, however, no charge was accumulated on acondenser 51 due to the fact that junction point 50 was connectedthrough the normally drawn up contact 44 to negative battery. It is tobe appreciated that the relay 43 follows the energization of thetransmission line 14 in accordance with signals impressed thereon torelease the contact 44 each time the transmission line 14 is interruptedby a spacing signal impulse. Release of contact 44 thereupon permits acharge to be impressed through junction point 50 to the plate of thecondenser 51, however, the R. C. value of this circuit is such thatinsufficient charge is accumulated to raise the potential at thejunction point 50 a suflicient amount so that the voltage impressed onthe starter anode of the cold cathode tube 52 is sufiicient to fire thistube. The voltage at junction joint 50 and on the starter anode does notrise to sufiicient voltage because the line relay 43 is again energizedby a marking or current impulse to move the contact 44 into engagementwith its lower contact to discharge the condenser 51.

The value of resistance 49 and capacitance 51 should be selected so thatthe tube 52 will not be fired during the normal transmission of anysignals over the transmission line 14, but only upon the occurrence of aprolonged break in the transmission line which is greater than the timeoccupied for the transmission of any signal over the line. Theresistance 49 is made adjustable in order that the charging circuit maybe responsive to various time breaks in the transmission line 14, whichmay occur due to the change in number of code impulses comprising asignal or as a result in a change in the transmission speed of thesignals impressed on the line 14.

When the left-hand coil of the relay 40 operates to open thetransmission line 14 the contact 42 thereby releases the relay 43 tocause the contact 44 to move from engagement with its lower contact andthe discharge circuit previously traced is interrupted. Closure of thecontact 41 associated with the left-hand coil of the relay 40 alsocompletes an auxiliary charging circuit for the condenser 51 which maybe traced from positive battery through the contact 41, through theright-hand coils of the relay 40, through a varistor 54, through aresistance 55, through the resistance 49 to the junction point 50 to thecondenser 51. The values of resistance 49 and 55 are rather high, hencethe charge built up at junction point 50 is not immediately ofsufficient value to fire the cold cathode tube 52.

During the time that the charge is building up at the junction point 50the contact 44 is positioned in engagement with its upper contact tocomplete an energizing circuit for the relay 33 which may be traced frompositive battery through the windings of the relay 33, through thecontact 46, through the now drawn up contact 4'7 of the relay 40, over alead 56, through the now released contact 44 of the relay 43 to negativebattery. Energization of the relay 33 completes a locking circuit whichmay be traced from positive battery through the windings of the relay33, through a now drawn up contact 57, over the lead 56, through thereleased contact 44 of relay 43 to negative battery.

Energization of the relay 33 also draws up the contact 32 intoengagement with a stationary contact 58 to complete an energizingcircuit for a relay 59 which may be traced from positive battery throughthe now closed contacts 32 and 58 of the relay 33, over a lead 61 andthence to the windings of the relay 59 to negative battery. Energizationof the relay 59 completes a locking circuit therefor which may be tracedfrom positive battery through a normally closed contact 62 associatedwith the function lever 23, through a normally closed contact 63associated with the function lever 22, over a lead 64, through a nowdrawn up contact 66 of the relay 59 through Winding of relay 59 tonegative battery. Closure of the contact 66 having positive batterythereon, also completes a circuit to operate an indicating lamp 67 whichapprises the operator at this station that his printing telegraphapparatus is in running condition. Energization of the relay 5'9simultaneously effectuates the closure of the contact 28 to complete theenergizing circuit for the motor 27 of the printing telegraph apparatuslo cated at station 10.

After a period of time sufiicient charge is accumulated on the condenser51 to raise the potential at junction point 50 to a value sufiicient tocause the potential on the starter anode of the tube 52 to rise to avalue whereby the tube 52 is placed in a conductive state. When the tube52 commences to conduct, a circuit is completed from positive batterythrough the drawn up contact 41 of the relay 40 through the right-handwindings of the may 40, through the varistor 54 to the anode of the tube52 and hence to the cathode of this tube which is connected to negativebattery. When tube 52 commences to conduct, current flows through theright-hand windings of the relay 4% to set up a magnetic field whichnullifies the eifect of the previously energized left-hand windings ofrelay 40; thus relay 40 will release all of its associated contacts 41,42, 47, and 48. Upon release of the contact 42, the transmission line isagain closed to apply nor mal energizing current over this line to againre-energize the relay 43. Energization of the relay 43 moves the contact44 from its stationary upper contact thereby disrupting the previouslytraced locking circuit for the relay 33. Of course, the release of thecontact 41 of the relay 4t removes positive potential from the anode ofthe tube 52 thereby causing this tube to again assume a nonconductivecondition.

Considering now the events that occur at all the other receivingstations 11, 12 and 13 when the contact 42 contained in the transmissionline 14 at station 10 is: opened for a prolonged period of time, it willbe noticed that the line relays 43 at all the stations will bedeenergized. Considering station 11 as a typical outlying receivingstation the de-energization of the relay 4-3 causes. the contact 44thereat to move from engagement with its lower stationary contact intoengagement with its upper stationary contact. As previously indicatedwith respect to circuits shown at station 10 a charging circuit for thetube 52 exists which is traced from positive battery through thewindings of relay 33, through the nor mally closed contact 46, throughthe unoperated con tacts 4'7 and 48, through the resistance 49 to thejunction point 50. When the contact 44 moves into engagement with itsupper contact negative battery which was applied. to junction point 56is removed whereupon the condenser 51 at this station commences toaccumulate a charge and which after a relatively small period of time,as determined by the value of the resistance 49 and the capacitancevalue of the condenser 51 raises the potential of the: junction point561! and hence of the start anode of thetube 42 to sufficient magnitudeto cause this tube to cornmence conduction and thereby establish anenergizing circuit for the tube which may be traced from positivebattery through the windings of the relay 33 through thenormally closedcontact 46 of the relay 33, through the normally unoperated contact 47of the relay 40, through the tube 52 to negative battery.

Energization of the relay 33 follows, and the make before break contact57 is drawn up to establish a locking circuit for the relay 33 which maybe traced from positive battery through the windings of relay 33 throughthe now drawn up contact 57 through the withdrawn contact 44 of thede-energized line relay 43 to negative: battery. Energization of therelay 33 also opens the hi a til)

contacts 46 to withdraw the source of positive battery from the anode ofthe tube 52 thereby restoring this tube to its normal nonconductivestate. Energization of the relay 33 also draws up its movable contact 32into engagement with the fixed contact 58 to again complete anenergizing circuit for the motor control relay 59 lo cated in thisstation. Energization of the relay 59 draws up its contact 28 tocomplete an energizing circuit for the motor 27 and simultaneouslytherewith the contact 66 closes to complete a locking circuit for therelay 59 which may be traced from positive battery through the contacts62 and 63 located at station 11 over the lead 64 through the now drawnup contacts 66 of the relay 59 and from there through the windings ofthe relay to negative battery. Again an indicating lamp 67 at thisstation is also operated upon closure of the contact 66.

When the line contact 42 at the calling station 10 is again closed aspreviously described, the line relays 4-3 at the calling station and allthe outlying stations are also re-energized moving the associatedcontacts 44 back into engagement with the lower contacts. Upon this moveof the contacts 44, the source of negative battery for the lockingcircuits for the relays 33 are removed, consequently these relays arede-energized to assume the normal unoperative conditions as shown in thedrawings. The system is now in such a condition that the motors 27 ateach of the stations 10, 11, 12, and 13 are in running condition and theprinting telegraph apparatus at each of these stations is in conditionto perform functions or record indicia in accordance with the signalsimpressed on the transmission line 14.

Now the initiating operator at station in depresses a key lever in hisprinting telegraph apparatus which is indicative of the letter A, hencecausing a movement of i the function lever 24 to close a contact 71.Actuation of the key lever representative of an A signal causes arecording of the letter A at the initiating station and at all theoutlying receiving stations. Closure of the contact 71 completes anenergizing circuit for the relay 36 which may be traced from positivebattery through the now closed contact 71, through normally closedcontacts 72 of the deenergize.d relay 39, through contacts 73, throughthe windings of the relay 36 to negative buttery. Energization of therelay 36 completes a locking circuit therefor which may be traced frompositive buttery through the pair of now closed contacts 32--3i of relay33, through a now closed pair of make before break contacts 74; throughthe windings of the relay 36 to nega tive battery. Closure of thecontacts associated with the relay 36 also completes an auxiliarylocking circuit for the motor control. relay 59 which may be traced frompositive battery through a pair of now closed contacts 76 of the relay56, over the lead 64 through the now closed contacts 66 and finallythrough the windings of the motor control relay 59 to negative battery.Closure of this auxiliary locking circuit for the motor con trol relay59 permits the initiating station to respond to all subsequentlytransmitted signals over the transmission line.

When the call contacts 71 were closed, an additional circuit wascompleted to an answer back magnet '78Which is traceable from positivebattery through the now closed contact 71 through the normally closedcontacts '72 the relay 39 and through the windings of the magnet '72; tonegative battery. Energization of the magnet causes its armature to bedrawn up and a mechanism atached thereto causes the answer back keylever 18 to be operated thereby actuating a recordation at theinitiating, station and all the outlying stations of a signal indicativeof the operation of the answer back key lever.

When the relay 36 at station 10- operates, its contact 35 closes toimpress positive battery through the normally closed contact pairs 32-34over the now closed contacts 35 over a lead 79, over a lead 81 throughthe windings of the relay 39, through a junction point 32 through aresistance to negative battery. However, the relay 39 is not operated atthis time due to the fact that the closure of the contacts 71 impressespositive battery through the normally closed contacts 72, through aresistor 83 to the junction point 82. Inasmuch as this circuit impressesa positive potential at the junction point 82 this circuit in eflfectacts as a short circuit for the relay 39 and precludes its operationuntil such time as the contacts 71 open. Contacts 71 will open followinga recordation of the A signal at the station whereupon the shunt circuitto junction point 32 is opened thereby permitting the relay 39 to nowoperate. Operation of the relay 39 draws up a contact 84 to complete anenergizing circuit for a busy lamp 86 which may be traced from positivebattery through the normally closed contact pair 32-34 of the relay 33over the lead 37, through the drawn up contacts 84 of the relay 39,through the busy lamp 86 to negative battery.

The operator at station 10 now sends call characters which areindicative of the stations desired to receive the forthcoming message.The transmission of a signal representative of the letter B which isalso the call letter for the station 11 causes a recordation of theletter B at all of the stations in the system. Receipt of a signalindicative of the letter B at the station 11 causes the function lever25 to close the contacts 71 thereat. As described in relation to theoperation of the circuits at the station 10, closure of the contacts 71efiectuates an operation of the relay 36 to complete an auxiliaryholding circuit for the motor control relay 59 located at this station.Closure of the contact 71 also effectuates an operation of the answerback magnet 78 located at this station which operation causes the keylever 19 to be operated thereby causing this station to transmit asignal representative of the answer back designation of this station.This signal again is recorded at all of the stations in the system. Whenthe contacts 71 at station 11 open following recordation of the callletter, the relay 39 at this station operates to effect an illuminationof the busy lamp 86.

The operator at station 10 now transmits a signal indicative of thespace function which action causes an operation of the function lever 22to move the contact 63 from engagement with the upper stationary contactto an engagement with the lower stationary contact. This operation alsooccurs at all of the outlying stations in the system whereupon thosestations, whose relays 36 have not been operated to complete theauxiliary locking circuits, are placed in the unoperated condition byhaving the locking circuits for the motor control relays 59 in terruptedat contacts 63 thereby releasing the energizing circuits for the motors27 at each of these stations. It may be thus appreciated that thestations with the deenergized motors will not effect a recording of thesubsequently transmitted messages.

At the unoperated stations the movement of the contact 63 intoengagement with the lower stationary contact completes a circuit whichmay be traced from positive battery through the normally closed contacts62, through lower contacts 63, through the windings of the relay 39 tonegative battery, thereby energizing this relay to cause its contacts tobe drawn up. Assuming for purposes of illustration that station 11 isnonselected then it may be seen that the drawing up of the contact 38completes a locking circuit for the relay 39 which may be traced frompositive battery through the normally closed contacts 32-34, over thelead 37, through the now closed contacts 38, through the windings of therelay 39 to negative battery. It is to be recalled that energization ofthe relay 39 also closes the contacts 84 thereby completing thepreviously traced energizing circuit for the busy lamp 86 hence theattendants at the unoperated outlying stations are apprised of the factthat the system has certain stations which are in a selective conditionin anticipation of the transmission of messages 8 through the system,but that this station is an unselected station and is not going torecord these messages.

At the stations that are selected to receive the messages both the onlamp and the busy lamp 86 are illuminated, hence the attendants at thesestations are informed of the fact that a message is forthcoming throughthe system and the station is going to record a message. It is ofinterest to note that at the nonoperated stations, the start switch 31is disconnected from the source of positive battery due to the closureof the contact 38 and the failure of the relay 36 to be energized toclose its contact 88. At all the selected stations including theinitiating station, the start switch 31 is connected to the source ofpositive battery which circuit may be traced from positive batterythrough the normally closed contact pair 33-3 of the de-energized relay33, through the now drawn up contact 88 of the relay 36 over a lead 89to the lower terminus of the start switch 31.

Following transmission of the message it is desired that the system berestored to its unoperated condition preparatoiy to the transmission ofsubsequent messages to different arrangements of stations. The operatorat the initiating station 10 will close his start switch 31 which aspreviously described with respect to the initiation of a call to theoutlying station causes the transmission line contact 42 to openwhereupon the relays 33 are operated at all of the outlying systemsincluding those which were nonselected. Operation of the relay 33 causesthe contact 32 to move from engagement with the contact 34 hence theholding circuits for the relays 39 and 36 are broken at all of theselected stations including the initiating station 16. Operation ofrelay 33 is also followed by an energization of the motor controlcircuit at all of the nonselected stations, hence it may be comprehendedthat all the motors at all the stations in the system are now in arunning condition. The operator at the transmitting station thentnansmits a signal which is indicative of a carriage return functionthereby effectuating a movement of a function lever 23 to open thecontacts 62 at all of the outlying stations causing positive battery tobe removed from the motor control relays 59 thereby permitting thecontacts associated therewith to open and as a result all of the motors27 at all of the stations are shut off. The system is now in conditionfor the setting up of another pattern of stations to receive messages.

It is to be understood that the above-described arrangements ofcircuits, components and elemental parts are simply illustrative of anapplication of the principles of the invention and that many othermodifications and rearrangements may 'be made without departing from theinvention.

What is claimed is:

1. In a multistation communication system wherein each station ispermanently connected to a signaling line and each station includes anormally de-energized apparatus, a control circuit for operating saidapparatus, an electronic tube, first and second time delay chargingcircuits adapted to operate each tube, discharge means for renderingsaid charging circuits ineffective, an initiating relay circuit,selective means for energizing said initiating relay circuit to operatesaid control circuit to operate the apparatus at an initiating station,means for locking said apparatus control circuit in the operatedcondition, means operated by said selective means for rendering saiddischarge means ineliective and said first charging cincuit effective toopenate the tube, means operated by said tube for restoring saidinitiating relay circuit to the unoperated condition, means at allstations responsive to the operation of the selective means at any otherstation for rendering the associated discharge circuit ineffective andsaid second charging circuit effective to operate the associate tube,and means operated by the tube in response to actuation by said secondcharging circuit for operating the apparatus control circuit at thatstation.

2. In a multistation telegraph system wherein each station is operablyassociated with a single signaling channel and each station includes anormally unoperated motor control circuit, an initiating relay circuitfor operating said motor control circuit, an electronic tube, first andsecond time delay charging circuits adapted to operate each tube,discharge means for rendering said charging circuits ineffective,selective means for energizing said initiating relay circuit to operatesaid motor control circuit, means for locking said motor control circuitin the operated condition, means operated by said selective means forrendering said discharge means ineffective and said first chargingcircuit effective to operate the tube, means operated by said tube forrestoring said initiating relay circuit to the unoperated condition,means at all stations responsive to the operation of the selective meansat any other station for rendering the associated discharge circuitineffective and said second time delay circuit effective to operate theassociated tube, and means operated by said tube for operating the motorcontrol circuit at that station.

3. In a telegraph system having a plurality of stations seriallyinterconnected by means of a normally energized signalling line, anormally unoperated motor at each station, means at each station foroperating said motor which comprises a line contact, a line relayenergized by said energized signaling line, a tube, a charging circuitnormally tending to fire said tube, a discharge circuit maintained bysaid line relay for precluding the charging circuit from firing thetube, a normally open start relay circuit adapted to operate s aidmotor, selectively operable relay means for opening said line contact tode-energize said line relay whereupon said charging circuit fires thetube l'dfifil a predetermined time delay, means actuated by thede-energization of the line relay and the selectively operable relaymeans for closing the start relay circuit for the motor, means operatedby the start relay circuit for locking the motor in the runningcondition, and means operated by the firing of the tube for closing theline contact to restore the line relay to its initial condition wherebythe start relay circuit is restored to the normal open condition.

4. In a telegraph system as defined in claim 2 which includes meansoperated by the firing of the tube for deenergizing said tube.

5. In a telegraph system, a line circuit, stations connected in seriesin said line circuit, a contact in the line circuit at each station, anormally unoperated motor at each station, circuit means at each stationfor initiating operation of the motor thereat and for opening the linecontact thereat, means operated by the initiating means for locking themotor in the operative condition, an electronic tube at each station,first and second charging circuits associated with and adapted tooperate each tube, said charging circuits having different periods ofoperation, means at each station for rendering the charging circuitthereat ineiiective, means at the initiating station responsive to theopening of the line contact thereat for rendering the first chargingcircuit efiective whereby the tube is rendered operative after a firstperiod of time, means operated by the tube for rendering ineffectivesaid initiating circuit means for said motor, means at all of the otherstations operated by the opening of said line circuit for rendering saidsecond charging circuits effective whereby said tubes thereat arerendered conductive after a second period of time, and means operated bythe operation of the tubes at these other stations for renderingeiiective the initiating circuits for the motors thereat.

6. in a telegraph system as defined in claim 4 which includes meansoperated by de-energization of the initiating circuit at the initiatingstation for rendering the tube thereat nonconductive.

7. In a telegraph system as defined in claim 4 which includes meansoperated by initiating circuit at said other stations for locking themotor in the operative condition, and means operated by the initiatingcircuit at these other stations for rendering the tube nonconductive.

8. In a telegraph system having a plurality of stations permanentlyassociated With a signaling line, each of said stations comprising anormally unoperated motor for driving the telegraph equipment thereat, aline contact at each station, a tube at each station, a first chargingcircuit adapted to operate said tube after a relatively long timeduration, a second charging circuit adapted to operate said tube after arelatively short time duration, means at each station for precludingeach charging circuit from operating the associated tube, an initiatingcircuit at each station for opening said line contact to renderefiective said first charging circuit to operate said tube after saidrelatively long time duration, relay circuit means actuated by saidinitiating means for operating the motor, means operated by the relaycircuit means for locking the motor in operative condition, meansoperated by the firing of the tube for closing the line contact torestore the relay circuit means to the initial condition, means at eachstation responsive to the opening of the line contact at any otherstation for rendering ineffective said precluding means and renderingefi'ective said second charging circuit to fire the tube thereat, andmeans operated by the firing of the tube at all but the initiatingstation for operating the relay circuit means thereat to operate andlock the motor in the operative condition.

9. In a telegraph system as defined in claim 8 wherein means at aninitiating station are actuated by the firing of the tube thereat torestore the line contact, and means at all the outlying stationsactuated by the reclosure of the line contact for restoring the tube andrelay circuit means to the unoperated condition.

References Cited in the file of this patent UNITED STATES PATENTS

